In-depth growth of micro-cracks in a ferritic-martensitic steel

含软、硬相材料的疲劳裂纹扩展与软、硬相的空间分布密切相关。在铁素体-马氏体钢中，马氏体区域是阻止微裂纹扩展的屏障。一旦克服了这个障碍，裂缝就会沿着相当曲折的裂缝路径延伸。这意味着对这些疲劳裂纹进行详细的断裂力学分析是非常困难的。这一建议旨在开发铁素体-马氏体钢疲劳裂纹的加载参数，此外，在了解马氏体相的作用，一旦第一个障碍已经突破。在这种情况下，考虑裂纹的三维形状是很重要的，因为在表面上被马氏体区域阻止的裂纹可能会继续向深度方向延伸。

The extension of fatigue cracks in materials containing soft and hard phases is strongly dependent on the spatial distribution of the phases. Martensite region act as a barrier against micro-crack extension in a ferritic-martensitic steel. Once this barrier has been overcome the crack extends along rather tortuous crack paths. This implies that a detailed fracture mechanics analysis of these fatigue cracks is very difficult. This proposal aims at developing loading parameters for fatigue cracks ina ferritic-martensitic steel, and , in addition, at understanding the role of the martensitic phase once the first barrier har been breached. In this context, it is improtant to take the three-dimensional shape of the crack into accout, as a crack which has been stopped by a martensite region on the surface may continue to extend in depth direction.